1. Field of the Invention
The present invention relates to a hand-off method using edge nodes in a mobile ad-hoc network to promptly detect mobility of a mobile device moving into the mobile ad-hoc network, and to configure an address by broadcasting an Internet gateway advertisement message (IGAM) so that the edge nodes in the mobile ad-hoc network satisfy the specification of a mobile Internet Protocol version 6 (IPv6).
2. Description of the Related Art
An ad-hoc network is a temporarily and autonomously constructed network including a plurality of nodes having mobility. The ad-hoc network has been developed to construct a temporary network in an area where there is no infrastructure network, or where it is not easy to deploy a network based on an infrastructure network. It is expected that the mobile ad-hoc network technology is applicable to diverse applications such as home networking, a sensor network, and a personal area network. To this end, the mobile ad-hoc network is under development as a next-generation network.
FIG. 1 illustrates a mobile ad-hoc network. Referring to FIG. 1, in the mobile ad-hoc network, mobile nodes communicate with each other according to peer-to-peer (P2P) using an air interface. As a global connectivity is supported between an infrastructure network and the mobile ad-hoc network, existing wireless LAN services can be expanded and various services can be provided to the nodes in the mobile ad-hoc network via the Internet.
A mobile ad-hoc network routing protocol enables communications among mobile ad-hoc nodes, and has been developed with the advent of the mobile ad-hoc network in 1970's. The standardization of the mobile ad-hoc network routing protocol is in progress at the Internet Engineering Task Force (IETF) mobile ad-hoc network (MANET) working group.
The MANET routing protocol is categorized into a proactive protocol and a reactive protocol.
The reactive routing protocol searches a route in response to traffic being generated. Route information is stored to each node located along a route, but is discarded if the route is not utilized for a predetermined time. A mobile node moving into the MANET determines its mobility from prefix information included in the IGAM, and configures an address. According to the reactive routing protocol, as the prefix information is not regularly provided, it is hard to determine the node mobility.
The proactive routing protocol enables the entirety of the mobile nodes to maintain the latest route information, and advertises routing information all over the network periodically or in response to changes being made to a network topology, so that the mobile nodes can update their routing information. The proactive routing protocol can route packets along an optimum route at all times without suffering from a delay, and enables the mobile devices entering the MANET to easily detect their mobility. However, when periodically transmitting the IGAM according to the mobile IPv6 specification, the entire network is subjected to a control packet overhead.